1. Field of the Invention
The invention relates to oral compositions and methods employing such compositions for the remineralization of dental enamel.
2. The Related Art
In the mouth, there is a natural equilibrium between hydroxyapatite being dissolved from the enamel of teeth and hydroxyapatite being formed on or in the teeth from substances occurring naturally in the saliva. This equilibrium is shifting continuously. Among other factors, it is determined by diet and physical condition. If the equilibrium is such that hydroxyapatite is dissolved, a cariogenic condition arises which is referred to as demineralization. If the equilibrium is such that hydroxyapatite is being formed in demineralized enamel, this is referred to as remineralization. By remineralization, pre-existing tooth decay and caries can be reduced or eliminated by natural means.
It has long been known that fluoride-providing compounds, even in low concentrations, promote the remineralization process. They thereby reduce pre-existing carious conditions in the tooth structure. Fluoride is most effective during the developmental years from childhood to young adulthood. Improved remedies are necessary, especially beyond the formative years.
Attempts have been made to arrest or prevent progression of caries by incorporation of calcium and phosphate ions through dietary and dentifrice means. A significant hurdle to this approach has been maintaining the calcium and phosphate ions available in a non-precipitated form. Two phase or separately compartmented calcium and phosphate compositions have been proposed. GB Patent 1,408,922 (Raff et al.) suggests a two-compartment tube, the first being filled with a toothpaste containing calcium chloride and the second containing disodium hydrogen phosphate. Upon dispensing, the compositions are mixed thereby causing the precipitation of calcium phosphate onto the teeth.
A similar approach is reported by Tung in U.S. Pat. No. 5,037,639 and U.S. Pat. No. 5,268,167. The restorative compositions disclosed therein employ amorphous calcium phosphate or solutions which will form amorphous calcium phosphate suspended in a carrier. Suitable carriers were said to include gels, chewing gum, powders, mouthrinses, carbonated solutions and toothpaste. These compositions are said to have long range structure; however, they are thought to be homogeneous when measured on an Angstrom Scale. Under physiological conditions the amorphous calcium compounds have high solubilities, high formation rates and high rates of conversion to apatite. The rates of formation and conversion allow remineralization of the dental tissue to occur at a greater speed. Doubts have been raised however with respect to the efficacy of such treatment. Better systems need to be developed.
Accordingly, it is an object of the present invention to provide an oral product and method for building stronger, healthier teeth.
Another object of the present invention is to provide an oral product and method for remineralizing enamel which can be accomplished by a consumer without intervention of a dentist.
These and other objects of the present invention will become more readily apparent through the following summary and detailed discussion.